What is a physician specializing in the treatment of diseases associated with blood called?

The correct answer is hematologist. A hematologist is a physician who specializes in diagnosing and treating diseases and disorders of the blood. This includes conditions such as anemia, clotting disorders, leukemia, and lymphoma. Hematologists possess in-depth knowledge about blood composition, various components of the blood, and how these elements can be affected by different diseases.

The other choices represent different specialties: a hematopathologist focuses specifically on the examination of blood and bone marrow under a microscope, often working with slides or tissue samples to provide diagnoses. An oncologist specializes in cancer treatment, which can overlap with hematological cancers but is broader in scope than just blood diseases. A pathologist examines tissues and fluids to make diagnoses but does not specialize exclusively in blood-related conditions. Each of these specialties plays a crucial role in the medical field, but the hematologist primarily focuses on blood diseases.